1. Field of the Invention
The present invention relates to a video equipment suited to be used to, for example, display a picture screen in an arbitrary size at an arbitrary position on a display screen. More particularly, the present invention is designed to avoid making the display position of a picture screen, when the size of which has been changed, appear unnatural.
2. Description of the Related Art
A reduced-size sub or slave picture screen as well as a main picture screen is displayed on a display screen in a video equipment, such as a television receiver. In the video equipment of this type, a device which allows the size of the slave picture screen to be arbitrarily changed is provided. In case of changing the size of the slave picture screen in this way, the display screen is equally divided by two in the horizontal and vertical directions or into four regions (I) to (IV) totally, as shown in, for example, FIG. 3. The size of the picture screen is changed in accordance with each of these regions.
That is to say, if the center of the slave picture screen is in the upper-left region (I), for example, size change is made centered around the upper-left portion. Likewise, if the center of the slave picture screen is in the upper-right region (II), size change is made centered around the upper-right portion. If the center of the stave picture screen is in the lower-left region (III), size change is made centered around the lower-left portion. Further, if the center of the slave picture screen is in a lower-right region (IV), size change is made centered around the lower-right portion. By doing so, it is possible to make the display position of the picture screen appear unnatural less frequently or to avoid losing the picture screen due to the size change.
In the video equipment of this type, there is further proposed a device capable of arbitrarily changing the display position of a sub or slave picture screen. If a slave picture screen A shown in, for example, FIG. 4 is magnified, the slave picture screen A is magnified to a slave picture screen B since the center of the slave picture screen A is in the region (I). Then, if the size of the slave picture screen B is reduced, a resultant reduced-size picture screen C is as shown in FIG. 4 since the center of the slave picture screen B is in the region (II). In other words, the display position of the slave picture screen changes according to the magnification/reduction of the slave picture screen.
In contrast, there is also proposed a method of magnifying/reducing the size of a slave picture screen with the center of the slave picture screen fixed. In this method, however, if the size of a slave picture screen A shown in, for example, FIG. 5 is magnified, a slave picture screen B is obtained as shown in FIG. 5. If a slave picture screen A' in FIG. 5 is magnified, however, a slave picture screen B' is obtained and a part of the picture screen B' (oblique line portion) is lost as shown in FIG. 5. This loss occurs irrespectively of a user's intent, which might possibly cause various problems in the video equipments.
This application has been made under the above circumstances. Problems to be solved are that if the display position of a picture screen can be arbitrarily changed, the changed display position as a result of magnification/reduction of the picture screen appears unnatural or a part of the picture screen is lost. Thus, various problems possibly occur in the conventional device.